Suspension for a non-driven steerable vehicle wheel

ABSTRACT

Wheel suspension for a non-driven steerable vehicle wheel, comprising a kingpin ( 3 ) fixed in a front axle member ( 1 ), and having upper and lower bearings ( 17, 18 ) by means of which a wheel spindle ( 12 ) is pivotable relative to the member. The upper bearing ( 17 ) is a taper roller bearing with an inner ring ( 23 ), which is made in one piece with a spacer sleeve ( 24 ), which is clamped against the member. An elastic sealing ring ( 29 ) is held between the spacer sleeve and a surrounding cylindrical surface on the upper spindle ear ( 13 ) of the spindle.

The present invention relates to a wheel suspension for a non-drivensteerable vehicle wheel, comprising an axle member, which at each endhas a conical through-bore, which holds a conical central portion of akingpin, which is provided with kingpin ends extending outside the boreinto the member, and a spindle unit, having, firstly, spaced upper andlower spindle ears holding bearings into which the kingpin ends extendand of which the upper bearing is a roller bearing and the lower bearingis a journal bearing, and, secondly, an axle end on which a wheel hub isintended to be mounted.

The most common type of steering knuckle arrangement for trucks has thespindle unit mounted in a taper roller bearing at the upper end of thekingpin and a journal bearing at its lower end. The upper bearing takesup both axial and radial forces while the lower bearing only takes upradial forces. In such a spindle bearing, the axial force on the upperbearing is load-dependent, i.e. the axial load on the bearing varieswith the total weight of the vehicle. When taking a curve, the radialforces on the lower bearing from the kingpin will be such that theystrive to tip the lower bearing bushing in its seat in the lower spindleear. Since the bushing is forced into its seat and the kingpin ismounted with the minimum possible play in the bushing, the bushingcannot even out the force couples which apply an asymmetric load. Thisresults in the upper and lower areas of the bearing race being subjectedto radial forces and greater wear than the middle portion, and this inturn can lead to gaps occurring after a relatively short time whendriving with heavy loads on winding roads.

The purpose of the present invention is to achieve a wheel suspension ofthe type described by way of introduction with a lower kingpin bearingwhich has a longer life than previously known bearings of the type inquestion.

The purpose of the present invention is to achieve a wheel suspension ofthe type described by way of introduction, which makes more rapid andsimpler assembly possible of the upper roller bearing, so that assemblycosts can be appreciably reduced.

This is achieved according to the invention by virtue of the fact thatthe roller bearing has an inner ring, which is made in one piece with aspacer sleeve having an end surface abutting it a surface fixed relativeto the axle member, said surface surrounding the conical bore, and thatan elastic sealing ring abuts against an external cylindrical surface onthe spacer sleeve and an opposing internal cylindrical surface on thespindle ear.

The embodiment according to the invention permits, after forcing thesealing ring onto the spacer sleeve portion of the bearing inner ring,all of the components in the upper bearing, i.e. the bearing, the spacersleeve and the seal, to be mounted as a unit, which means that theassembly can be automated with advantage.

The invention presupposes that by making the components with narrowertolerances than previously it is possible to eliminate the need forshims and is based on the fact that increased production costs for thecomponents will in this case be more than compensated for in reducedassembly costs.

In a preferred embodiment, the exterior surface of the spacer sleeve isprovided with a peripheral groove so that a radially outwardly directedlower flange is formed, the upwardly facing surface of which, after thesealing ring has been slipped onto the spacer sleeve, serves as anabutment surface and assures that the sealing ring is retained in placedduring the assembly of the bearing.

In a further development of the wheel suspension according to theinvention, the spacer sleeve has an inner diameter which is greater thanthe outer diameter of the portion of the kingpin surrounded by thespacer sleeve. This, in combination with suitable adapting of thedimensions of the spacer sleeve to the clamping force makes it possible,with the clamping force, to affect the deformation of the spacer sleeveaxially to such an extent that minor tolerance deviations can becompensated for.

The invention will be described in more detail below with reference toan example shown in the accompanying drawing, which shows a longitudinalsection through a wheel suspension according to the invention for atruck front wheel.

In the FIGURE, 1 designates one end of a front member in a motorvehicle. The member 1 has a bore 2 of truncated conical shape along mostof its length. A kingpin, generally designated 3, with a middle portion4 with the same conicity as the bore 2, is fixed in the bore. An uppercylindrical kingpin end 5 extends above an upper end surface 6 of themember 1 and has a threaded portion 7 at its very end. A correspondinglower cylindrical kingpin end 9, but without the threaded portion at thevery end, extends below a lower end surface 10 on the member 1.

A wheel spindle generally designated 12 has an upper spindle ear 13 anda lower spindle ear 14, which are each made with an individual bearingseat 15 and 16, respectively, for an upper taper roller bearing 17 and alower journal bearing 18, respectively. The lower journal bearing 18consists of an outer sleeve 18 a of an elastically deformable plasticmaterial and an inner sleeve 18 b of a bearing metal. The upper bearingrests with its outer ring 19 against an upwardly facing surface 20 ofthe upper bearing seat 15. The upper kingpin end 5 protrudes into theinner ring 23 of the upper bearing 17, which is made in one piece with aspacer sleeve 24, which abuts against the upwardly facing surface 6 ofthe member 1 with an end surface 25. By tightening a nut 26 screwed ontothe threaded portion 7, the bearing ring 23 is clamped with its spacersleeve 24 against the member 1 and is rotationally fixed. The lowerkingpin end 9 protrudes into the inner bearing sleeve 18 b of the lowerjournal bearing 18. Its outer sleeve 18 a is pressed into the bearingseat 16 in the lower spindle ear 14. The axial position of the bearing18 in the seat 16 is determined by a flange 18 c on the inner bearingsleeve 18 b, said flange forming an abutment against an end surface 40on the lower spindle ear 14.

The outer cylindrical surface of the spacer sleeve 24 is made with aperipheral groove 27, into which the sealing lips 28 on an elasticsealing ring (generally designated 29) extend and abut with their endsurfaces against the bottom of the groove 27. The flange 27 a formed bythe groove 27 forms an abutment which keeps the seal in place duringassembly. The portion 30 of the sealing ring 29 opposite the sealinglips 28 has an essentially L-shaped cross sectional profile and ismounted in a seat 31 in the upper spindle ear 13.

As can be seen in the FIGURE, there are no shims between the upwardlyfacing surface 6 of the member 1 and the end surface of the spacersleeve 25. This means that the upper bearing 17 with its integratedspacer sleeve 24 and sealing ring 29 mounted thereon, can be directlymoved down over the end 5 of the kingpin 3 and the end surface 25 of thespacer sleeve will be brought into abutment against the member surface 6and the end surface of the outer ring 19 will be brought into abutmentwith the upwardly facing surface 20 of the bearing seat 15. The bearingassembly, as well as the subsequent screwing on and tightening of thenut 26 can be done with advantage by a robot.

The bearing design described presupposes manufacture with narrowtolerances. A certain evening out of minor tolerance deviations can beachieved by axial deformation of the spacer sleeve 24 by tightening thenut 26. In order to provide space for the radial expansion whichaccompanies axial compression of the spacer sleeve 24, it has a somewhatgreater inner diameter than the outer diameter of the surrounded kingpinportion, so that a gap 32 is formed.

The upper spindle ear 13 has an inner threaded portion 33 above thebearing seat 15, into which an externally threaded flange 34 on a cover35 is screwed in, so that a space sealed off by the sealing ring 29 andthe cover 35 is formed for lubricant. The cover 35 is provided with alaterally directed grease nipple 36. The entry point of the thread isselected so that the grease nipple 36, after the cover 35 has beenscrewed down, will assume a predetermined position in which it is easilyaccessible during service. The lower spindle ear 14 has a correspondinginternally threaded portion 37, into which an externally threaded cover38 with a grease nipple 39 is screwed.

What is claimed is:
 1. Wheel suspension for a non-driven steerablevehicle wheel, comprising an axle member, which at each end has aconical through-bore, which holds a conical central portion of a kingpinwhich is provided with kingpin ends extending outside the bore into themember, and a spindle unit, having, firstly, spaced upper and lowerspindle ears, holding bearings into which the kingpin ends extend and ofwhich at least the upper bearing is a roller bearing, and, secondly, anaxle end on which a wheel hub is intended to be mounted, characterizedin that the roller bearing (17) has an inner ring (23), which is made inone piece with a spacer sleeve (24) having an end surface (25) abuttingagainst a surface (6) fixed relative to the axle member (1), saidsurface (6) surrounding the conical bore (2), and that an elasticsealing ring (29) abuts against an external cylindrical surface on thespacer sleeve and an opposing internal cylindrical surface (31) on thespindle ear.
 2. Wheel suspension according to claim 1, characterized inthat the end of the spacer sleeve (24) facing the axle member surface(6) is made with a radially outwardly directed flange (27 a) forming anabutment surface facing the sealing ring (29).
 3. Wheel suspensionaccording to claim 2, characterized in that said abutment surface formsone side surface of a groove, in the spacer sleeve (24), for the sealingring (29).
 4. Wheel suspension according to claim 1, characterized inthat the spacer sleeve (24) has an inner diameter which is greater thanthe outer diameter of the portion of the kingpin (3) surrounded by thespacer sleeve.
 5. Wheel suspension according to claim 3, characterizedin that the sealing ring (29) has a radially outer cylindrical portion,which is held in a seat in the upper spindle ear and at least oneradially inwardly directed sealing lip (28), which abuts against thebottom surface of the groove.
 6. Wheel suspension according to claim 2,characterized in that the spacer sleeve (24) has an inner diameter whichis greater than the outer diameter of the portion of the kingpin (3)surrounded by the spacer sleeve.
 7. Wheel suspension according to claim4, characterized in that the sealing ring (29) has a radially outercylindrical portion, which is held in a seat in the upper spindle earand at least one radially inwardly directed sealing lip (28), whichabuts against the bottom surface of the groove.